Engine combustion chamber valves are almost universally of a poppet type. A number of means exist for opening such valves including a cam on a rotating cam shaft, hydraulic pressure, electromagnetics, and others. Hydraulically actuated valves are typically spring loaded toward a valve-closed position and opened against the spring bias by the hydraulic pressure.
Because the valve should open and close very quickly, the spring is typically very stiff and is loaded to a high force under the relatively high hydraulic pressure needed to open the valve quickly against the high internal pressures of the combustion chamber. Therefore, when the valve closes, it impacts the valve seat at velocities that can create forces which eventually erode the valve or the valve seat or even fracture or break the valve.
Therefore, it is an object of the present invention to provide a means whereby the valve will be slowed or snubbed as it nears the valve seat so that the valve seats at an acceptable velocity.
It is an additional object of the present invention to provide a hydraulically actuated poppet valve having a snubbing valve positioned upstream therefrom, wherein the snubbing valve restricts fluid flow exiting the hydraulic cavity between the engine valve and the snubbing valve as the engine valve closes, thereby slowing the engine valve to an acceptable impact velocity.